1. Technical Field of the Invention
The present invention relates to plasma discharge devices.
2. Description of Related Art
A plasma discharge device in its most simple single element form includes at least an anode electrode and a cathode electrode spaced apart from each other to define a discharge cell. A low pressure atmosphere of a gas mixture, typically including an ionizable inert (noble) gas, is maintained between the electrodes. When a sufficient potential is applied between the anode and cathode electrodes, an avalanche breakdown of the insulating properties of the gas occurs and a current flows between the electrodes forming a plasma discharge. The plasma discharge in the discharge cell comprises energetic electrons, excited atoms and ions.
The collision of the energetic electrons in the plasma discharge with the gas atoms maintained in the discharge cell ionizes the gas atoms, with the ionized gas atoms emitting a wide spectrum of radiation in the form of photons of light. The characteristics of the ionizable inert gas or mixture of gases maintained in the discharge cell dictate the dominant wavelength of the photons of light radiated from the discharge cell. For example, neon gas atoms will emit visible red-orange photons of light when excited by a plasma discharge. Xenon gas atoms, on the other hand, will emit primarily invisible ultraviolet photons of light that are converted to visible light using UV-excitable phosphors.
The prior art further teaches the assembly of a plurality of individual discharge elements in a matrix configuration to form a panel plasma discharge display. In such multi-element plasma displays, a discharge cell is positioned at each of the points of intersection between orthogonally oriented rows and columns of wire conductors which comprise the anode and cathode electrodes. By selectively addressing the discharge cells through controlled application of a sufficient potential to individual ones of the orthogonal conductors, plasma discharges are generated in the discharge cells at the intersection points to produce a visible image having a predetermined two-dimensional shape.